\  7,  £  '  7/70' 


U.  S.  DEPARTMENT   OF   AGRICULTURE, 

BUREAU  OF  ENTOMOLOGY— BULLETIN  No.  95,  Part  II. 

L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


PAPERS  ON  CEREAL  AND  FORAGE  INSECTS. 


THE  MAIZE  BILLBUG- 


BY 


E.  O.  G.  KELLY, 

Entomological  Assistant. 


Issued  April  22,  1911. 


WASHINGTON: 

GOVERNMENT     PRINTING     OFFICE 
1911. 


BUREAU  OF  ENTOMOLOGY. 

L.  O.  Howard.  Entomologist  and  Chief  of  Bureau. 

C.  L.  Mablatt,  Entomologist  and  Acting  Chief  in  Absence  of  Chief. 

R.   S.  Clifton,  Executive  Assistant. 

W.  F.  Tastet,  Chief  Clerk. 

F.  H.  Chittenden,  in  charge  of  truck  crop  and  stored  product  insect  investigations. 

A.  D.  Hopkins,  in  charge  of  forest  insect  investigations. 

W.  D.  Hunter,  in  charge  of  southern  field  crop  insect  investigations. 

F.  M.  Webster,  in  charge  of  cereal. and  forage  insect  investigations. 

A.  L.  Qtjaintance,  in  charge  of  deciduous  fruit  insect  investigations. 

E.  F.  Phillips,  in  charge  of  bee  culture. 

D.  M.  Rogers,  in  charge  of  preventing  spread  of  moths,  field  work. 

Rolla  P.  Currie,  in  charge  of  editorial  work. 

Mabel  Colcord,  librarian. 

Cereal  and  Forage  Insect  Investigations. 

F.  M.  Webster,  in  charge. 

Geo.  I.  Reeves,  C.  N.  Ainslie,  J.  A.  Hyslop,  T.  D.  Urbahns,  W.  R.  Walton. 

W.  J.  Phillips,  E.  O.  G.  Kelly,  Geo.  G.  Ainslie.  Philip  Luginbill,  entomo- 
and  experts. 

W.  J.  Phillips,  E.  O.  G.  Kelly.  Geo.  G.  Ainslie.  Philip  Luginbill,  entomo- 
logical assistants. 

^Nettie  S.  Klopfer.  preparator. 


CONTEXTS. 


Page. 

Introduction 11 

History  of  the  species 12 

Injuries  since  1895 14 

Distribution 15 

Food  plants 15 

Description  and  life  history 16 

Number  of  generations 22 

Records  of  depredations 22 

Remedial  measures 22 


ILLUSTRATIONS 


Page. 
Plate  II.  Fig.  1. — Corn  plant  injured  by  the  adult  of  the  maize  billbug 
(Sphenophorus  maidis);  afterward  attacked  by  the  larva.  Fig.  2. — 
Corn  plant  showing  on  stalk  the  effects  of  feeding  by  adult  maize 
billbugs ;  effects  of  feeding  by  larvae  on  roots.  Fig.  3. — Corn  plant, 
much  distorted,  showing  suckers;  final  effects  of  feeding  of  adult 

maize  billbug 18 

III.  Corn  plants  showing  effects  of  feeding  of  adult  maize  billbugs  in  the 

field;  plant  at  left  not  attacked:  the  two  at  right  attacked  by  larvae.         18 

TEXT   FIGURES. 

Fig  .  5.  The  maize  billbug  (Sphenophorus  maidis  | :  Egss 16 

6.  The  maize  billbug:  Larva 16 

7.  Corn  plant  showing  result  of  attack  by  the  maize  billbug 18 

8.  Swamp  grass  attacked  by  the  maize  billbug 18 

9.  The  maize  billbug:  Pupa 19 

10.  The  maize  billbug:  Adult 21 

7923G0— Bull.  95— 11  m 


U.  S.  D.  A.,  B.  E.  Bui.  05.  Part  II.  C.  F.  I.  I..  April  22,  1911. 

PAPERS  ON  CEREAL  AND  FORAGE  INSECTS. 


THE  MAIZE  BILLBUG. 

(Sphenophorus  maidis  Chittn.) 

By  E.  O.  G.  Kelly. 
Entomological  Assistant. 

INTRODUCTION. 

There  are  several  species  of  the  genus  Sphenophorus  that  have  been 
reported  as  being  enemies  to  young  corn  in  early  spring.  Heretofore 
these  reports  have  always  been  made  in  connection  with  fields  of 
grass,  timothy  sod,  or  lands  recently  reclaimed  by  drainage,  and  the 
depredations  were  on  the  first  cultivated  crop  following  these 
conditions. 

Dr.  S.  A.  Forbes  a  records  eight  species  of  Sphenophorus  the  adults 
of  which  are  known  to  attack  young  corn.  Dr.  C.  V.  Riley,  in  the 
report  of  the  Commissioner  of  Agriculture  for  1881  and  1882,  records 
Dr.  L.  O.  Howard's  observations  on  the  habits  and  natural  history 
of  S.  rohustus  and  gives  a  description  of  the  imago,  larva,  and  pupa, 
Dr.  Howard  having  found  and  reared  these  from  specimens  taken 
from  young  corn  plants  at  Columbia,  S.  C.  Dr.  F.  H.  Chittenden, 
however,  in  a  paper  entitled  "  On  the  species  of  Sphenophorus  related 
to  pertinax  Oliv.,  with  descriptions  of  other  forms,"  h  with  refer- 
ence to  S.  rohustus,  says : 

This  species  ranges  from  Indiana  and  Michigan  through  Wisconsin,  Minne- 
sota, and  western  Kansas  to  California.  It  is  a  northern  form,  not  occurring  in 
the  East.  Nothing  appears  to  be  known  of  its  habits,  reference  to  rohustus 
and  its  injuries  to  corn  being  due  to  a  distinct  species,  my  S.  maidis. 

Dr.  Chittenden  had  before  him,  while  describing  S.  maidis,  among 
numerous  other  specimens,  the  one  specimen  from  Columbia,  S.  C. 
reared  by  Dr.  Howard.  According  to  his  statement  maidis  is  a  valid 
species  and  quite  distinct  from  S.  rohustus. 

a  Twenty-third  Report  of  the  State  Entomologist  of  Illinois,  1905. 
&Proc.  Ent.  Soc.  Wash.,  vol.  7,  p.  57,  1905. 

11 


12  PAPERS  ON  CEREAL  AND  FORAGE  INSECTS. 

Dr.  Chittenden  informs  the  writer  that  since  1895  complaints  have 
been  made  every  few  years  in  localities  in  Kansas,  South  Carolina. 
Georgia,  and  Alabama  of  injuries  to  corn  by  what  he  believes  to  be 
this  species  of  billbug.  The  species  has  been  quite  generally  confused 
with  Sphenophorus  pcrtinax  Oliv.  and  S.  rohustus  Horn,  by  both  of 
which  names  it  has  been  mentioned  in  economic  literature,  more 
especially  by  the  latter.  It  is,  however,  quite  distinct  from  either, 
in  fact,  different  from  any  billbug  known  to  inhabit  the  United 
States,  and  has  only  recently  been  described  as  new  to  science,  although 
Dr.  Chittenden  states  that  it  is  by  no  means  new  as  an  agricultural  foe. 

The  observations  on  the  maize  billbug  (Sphenophorus  maidis 
Chttn.)  given  herein  were  made  by  the  writer  between  June  and 
December,  1910. 

HISTORY   OF   THE   SPECIES. 

The  history  of  this  species,  the  writer  is  informed  by  Dr.  Chitten- 
den, is,  in  brief,  that  it  first  attracted  attention  in  Alabama  as  early 
as  in  1854;  again  in  the  same  State  in  1880;  in  South  Carolina  in 
1881;  in  Kansas  in  1895;  in  1901  it  again  did  injury  in  Kansas,  and 
in  1903  in  Georgia.  The  fact  that  the  insect  is  injurious  to  corn  in 
both  of  the  active  stages,  larva  and  beetle,  indicates  that  it  is  a 
more  or  less  permanent  pest,  whereas  several  of  our  equally  common 
corn  billbugs  will  eventually  disappear  with  the  reclamation  by 
draining  and  the  cultivation  of  the  soil  and  the  consequent  destruc- 
tion of  their  breeding  places. 

In  the  opinion  of  Dr.  Chittenden,  this  is  the  species  described  and 
figured  by  Townend  Glover  in  1855  °  as  the  "  billbug  "  or  '  corn  borer 
(Sphenophorus  ?),"  since  both  description  and  figure  do  not  apply 
to  any  other  billbug  known  to  breed  in  corn.  Glover  describes  the 
beetle  as  from  four-tenths  to  six-tenths  of  an  inch  in  length,  and  of 
a  reddish-brown  or  reddish-black  color,  and  the  rostrum  or  snout 
in  the  figure  can  not  belong  to  an}^  other  Sphenophorus.  None  of 
the  specimens  which  served  as  models  of  the  drawing  remains  in  the 
Government  collections.  The  billbug  was  reported  as  very  destruc- 
tive to  corn  in  many  parts  of  the  South  and  Southwest,  more  par- 
ticularly along  the  Pedee  River.  Injuries  were  reported  by  Senator 
Evans,  Gen.  Fitzpatrick,  and  Col.  Pitchlynn.  Senator  Evans's 
report  is  as  follow- : 

The  perfect  insect  eats  into  the  stalk  of  the  corn,  either  below  or  just  at 
the  surface  of  the  ground,  where  it  deposits  its  egg.  After  changing  into  a 
grub,  the  insect  remains  in  the  stalk,  devouring  the  substance,  until  it  trans- 
forms into  the  pupa  state,  which  occurs  in  the  same  cavity  in  the  stalk  occu- 
pied by  the  grub.  It  makes  its  appearance  the  following  spring  in  the  perfect 
state,  again  to  deposit   its  eggs  at  the  foot  of  the  young  corn  plants.     These 

"Agricultural  Report  of  the  Patent  Office  for  1S54   (1855),  p.  07,  pi.  4. 


THE   MAIZE   BILLBUG.  13 

insects  destroy  the  main  stem,  or  shoots,  thus  causing  suckers  to  spring  up,  which 
usually  produce  no  grain,  or,  if  any,  of  very  inferior  quality  to  that  of  the 
general  yield.  Swamp  lands  or  low  grounds  are  the  places  most  generally 
attacked. 

Senator  Evans  thus  is,  according  to  Chittenden,  to  be  credited 
with  the  discovery  that  the  larva  develops  in  the  stalk  of  corn  below 
the  ground,  and  not  in  decaying  wood,  as  contended  by  Messrs. 
Walsh  and  Riley  in  later  years.  The  insect  was  said  to  be  very 
destructive  in  Alabama,  from  which  State  the  specimens  chosen  for 
illustration  doubtless  came,  and  on  the  Red  River  in  Arkansas. 
With  little  doubt  it  was  the  same  insect  operating  in  Arkansas,  as  it 
is  now  known  that  this  species  ranges  between  South  Carolina  and 
Missouri. 

This  insect  was  observed  in  the  spring  of  1881  by  Dr.  L.  (X 
Howard,  at  that  time  assistant  to  Dr.  C.  V.  Riley,  Entomologist  of 
the  Department  of  Agriculture.  Dr.  Howard  was  at  once  sent  to 
Columbia,  S.  C,  to  investigate  the  injury  being  done  to  corn  by 
"  billbugs,"  and  the  following  account  of  these  investigations  is 
taken  from  the  report  of  his  observations:" 

The  species  found  near  Columbia,  S.  C,  is  8.  robustas  [now  8.  maidis].  In 
the  plantations  along  the  bottom  lands  of  the  Congaree  River  much  damage  is 
done  by  the  adult  beetle  every  year,  and  the  corn  not  infrequently  has  to  be 
replanted  several  times,  as  the  earlier  plantings  are  destroyed.  The  beetles 
are  first  noticed  in  the  spring  after  the  corn  is  well  up.  Stationing  themselves 
at  the  base  of  the  stalk,  and  also  burrowing  under  the  surface  of  the  earth 
slightly,  Lhey  pierce  the  stalk  and  kill  many  plants  outright,  others  living  U> 
grow  up  stunted  and  dwarfed. 

With  &.  sculptilis  [zew],  in  spite  of  the  damage  it  has  done,  the  earlier  stages 
remain  unknown,  Walsh  surmising  that  the  larva  breeds  on  rotten  wood,  so 
situated  that  it  is  continually  washed  by  water.  With  this  statement  in  my 
mind  I  was  prepared  to  doubt  the  statement  of  Mr.  W.  P.  Spigener,  of  Columbia, 
who  informed  me  that  the  "  grub  form  of  the  billbug  "  was  to  be  found  in  the 
corn,  but  a  couple  of  hours  in  the  field  convinced  me  that  he  was  right,  my 
previous  idea  having  been  that  he  had  mistaken  the  larva  of  Chilo  saccharalis 
for  the  weevil  grub.  I  searched  a  field  on  Mr.  Spigener's  plantation,  which  was 
said  to  be  the  worst  point  in  the  whole  neighborhood  for  bugs,  for  some  time 
before  finding  a  trace  of  the  beetle  in  any  stage,  but  at  last,  in  a  deformed 
stalk,  I  found  in  a  large  burrow,  about  at  the  surface  of  the  ground,  a  full- 
grown  larva.  After  I  had  learned  to  recognize  the  peculiar  appearance  of  the 
infested  stalks  I  was  enabled  to  collect  the  larvae  quite  rapidly. 

They  were  present  at  this  date  (Aug.  20)  in  all  stages  of  larval  development, 
but  far  more  abundantly  as  full-grown  larvae.  A  few  were  preserved  in  alcohol 
and  the  remainder  forwarded  alive  to  the  department,  but  all  died  on  the  way. 
Two  pupae  were  found  at  the  same  time;  one  was  preserved  in  alcohol  and  the 
other  forwarded  to  the  department.  The  beetle  issued  on  the  way,  and  from 
this  specimen  we  have  been  able  to  determine  the  species.  From  an  examination 
of  a  large  number  of  injured  stalks  it  seems  evident  that  the  egg  is  laid  in  the 

a  Report  of  the  Entomologist.  Department  of  Agriculture,  for  1881  and  1882, 
pp.  139-140. 


14  PAPERS  ON  CEREAL  AND  FORAGE  INSECTS. 

stalk  just  at  the  surface  of  the  ground,  preferably  ami  occasionally  a  little 
below.  The  young  larva?,  hatching,  work  usually  downward,  and  may  be  found 
at  almost  any  age  in  that  part  of  the  stalk  fruw  which  the  roots  are  given  out. 
A  few  specimens  were  found  which  had  worked  upward  for  a  few  inches  into 
the  first  section  of  the  stalk  above  ground,  but  these  were  all  very  large  indi- 
viduals, and  I  conclude  that  the  larva  only  bores  into  the  stalk  proper  after 
having  consumed  all  available  pith  below  ground. 

The  pupae  were  both  found  in  cavities  opposite  the  first  suckers,  surrounded 
by  excrement  compactly  pressed,  so  as  to  form  a  sort  of  cell. 

Wherever  the  larva  had  reached  its  full  size,  the  pith  of  the  stalk  was  found 
completely  eaten  out  for  at  least  5  inches.  Below  ground  even  the  hard  ex- 
ternal portions  of  the  stalk  were  eaten  through,  and  in  one  instance  everything 
except  the  rootlets  had  disappeared  and  the  stalk  had  fallen  to  the  ground. 

In  a  great  majority  of  instances  but  a  single  larva  was  found  in  a  stalk,  but 
a  few  cases  were  found  where  two  larva?  were  at  work.  In  no  case  had  an 
ear  filled  on  a  stalk  bored  by  this  larva.  The  stalk  was  often  stunted  and 
twisted,  and  the  lower  leaves  were  invariably  brown  and  withered. 

In  one  field,  which  had  been  completely  under  water  for  six  days  in  January, 
the  beetles  were  apparently  as  healthy  as  in  fields  which  had  remained  above 
water. 

INJURIES   SINCE    1895. 

The  records  of  reports  of  injury  which  follow,  received  by  Dr. 
Chittenden  during  the  past  decade,  substantiate  the  observations  of 
Dr.  Howard  made  in  1881,  and  add  as  well  to  our  knowledge  of  the 
life  economy  of  the  species. 

In  1895  this  billbug  was  destructive  in  three  localities  in  Kansas, 
complaints  all  being  made  during  the  first  week  of  May.  At 
Cedar  Yale  immense  damage  was  done,  the  insect  "  taking  whole 
fields  of  corn,  hill  by  hill."  Similar  injury  was  observed  at  Dexter 
and  Leon,  these  reports  having  been  made  by  Mr.  Hugo  Kahl  in  a 
letter  dated  July  27,  1898. 

The  following  year  Prof.  F.  S.  Earle  reported,  June  6,  injury  by 
this  species  at  Wetumpka,  Ala.,  on  the  Coosa  River,  where  there  was 
great  complaint  of  it  as  a  destructive  enemy  of  corn,  especially  on 
low-lying  bottom  lands.  The  insect  was  well  known  there  as  a  bill- 
bug,  and  was  not  found  on  hillv  land.  It  worked  below. ground,  and 
when  the  stalks  were  not  killed  outright  they  put  out  an  immense 
number  of  suckers.  The  beetles  were  most  destructive  to  early  plant- 
ings, corn  planted  after  the  middle  of  May  being  usually  little 
injured. 

In  1901  Mr.  J.  E.  Williams,  Augusta.  Butler  County,  Kans..  wrote, 
August  28,  of  injury  to  corn.  Attack  commenced  as  soon  as  the  corn 
came  through  the  ground,  and  the  billbugs  ate  and  dug  down  to  the 
kernel  and  devoured  that.  In  larger  corn  they  bored  into  the  stalk 
and  wintered  over  in  the  old  stalks,  usually  below  ground.  Whole 
fields  were  destroyed,  the  beetles  remaining  to  continue  their  work  on 
second  plantings.  The  insect  was  known  locally  as  the  u  elephant 
bug.''     September  G  Mr.  William-  sent  larva1  and  adults  and  their 


THE    MAIZE   BILLBUG.  15 

work  in  the  root-stalks  of  corn.  He  had  observed  that  the  eggs 
were  deposited  in  the  stalks,  and  that  these  serve  for  the  winter 
quarters  of  the  adults:  that  the  beetles  began  work  when  the  corn 
was  about  1  or  5  inches  high  by  inserting  their  beaks  in  the  young 
stalks  just  above  ground.  By  taking  hold  of  the  center  of  the  corn 
and  pulling  it  it  came  out.  as  it  Avas  nearly  severed  as  from  cutworm 
attack.  Stalks  that  had  been  preyed  upon  by  the  billbug  did  not 
yield  any  amount  of  seed.  Xo  injury  was  observed  to  crops  other 
than  corn.  Injury  was  only  in  lowlands,  and  the  principal  damage 
was  accomplished  before  the  woody  outer  shell  of  the  stalk  was 
formed.  The  beetles  were  active  chiefly  after  dark,  when  they  trav- 
eled, though  slowly,  from  one  place  to  another.  They  burrowed  in 
the  ground  during  the  day.  They  were  described  as  :;  cleaning  up 
everything  as  they  go.  rendering  the  crop  entirely  worthless.''  Sep- 
tember IT  another  sending  of  larvae,  pupa?,  and  imagos  were  re- 
ceived from  the  same  source.  Out  of  100  stalks  examined  by  our 
correspondent  only  10  were  free  from  the  ravages  of  this  billbug. 
At  this  date  of  writing  the  beetles  were  deserting  the  corn. 

In  1903  a  report  was  received  of  injury  by  what  was  with  little 
doubt  this  species  at  Griffin.  Ga..  although  no  specimens  were  re- 
ceived, as  in  all  preceding  instances  cited. 

DISTRIBUTION. 

This  insect  has  been  reported,  according  to  Chittenden:2  from 
Augusta,  Kans.  (E.  L.  Williams)  :  Riley  County.  Kans.  (P.  J.  Par- 
rott) ;  Florence.  Kans.;  Dadeville.  Ala.  (S.  M.  Robertson):  AVe- 
tumpka,  Ala.  (F.  S.  Earle)  :  Columbia.  S.  C.  (L.  O.  Howard)  : 
Ballentine.  S.  C.  (J.  Duncan)  ;  Texas  (Ulke.  1  ex.)  :  Michigan 
(Knaus).  It  has  also  been  reported  from  Texas  (T.  D.  Urbahns). 
and  the  writer  found  it  at  several  points  in  Oklahoma  and  Kansas. 
Owing  to  the  fact  that  representatives  of  the  species  have  been  taken 
in  such  widely  separated  localities,  it  is  very  probable  that  it  occurs 
over  the  entire  territory  between  South  Carolina  and  Texas  and 
northward  to  Kansas  and  Missouri. 

FOOD   PLANTS. 

The  adults  attack  young  corn  plants  and  probably  some  of  the 
coarser  grasses.  Dr.  Howard,  and  later  the  writer,  found  both 
adults  and  larvae  feeding  on  young  corn.  Mr.  Urbahns  found 
adults  at  base  of  swamp  grass  (Tripsacum  dactylohles)  in  consider- 
able numbers,  and  probably  larva?  and  pupae  of  the  species  in  this 
same  grass  (fig.  8).     Mr.  Urbahns  found  several  Sphenophorus  larvae 

aProc.  Ent.  Soc.  Wash.,  vol  7.  No.  1.  pp.  50-01.  1905. 


16 


PAPEi:>  ON  CEREAL  AND  FORAGE  INSECTS. 


in  burrows  in  this  swamp  grass  and  two  pupa?,  but  failed  to  rear 
them.     Dr.  Chittenden  determine!  these  pupae  a-  having  adult  char- 
-     :    v        Idis. 

DESCRIPTION  AND  LIFE  HISTORY. 


THE    EGG. 


-    D 


Eggs  were  found  by  the  writer  in  southern  Kansas  during  June 
in  puncture-  made  especially   for  them    <  fig.   7.   l>  i    in  young  corn 

plant-.  These  egg  puncture-,  which  the 
female  make-  with  her  beak,  arc  scarcely 
visible  on  the  outer  surface  of  the  -talk,  being 
only  a  -lit  in  the  -heath  of  the  plant,  through 
which  the  beak,  and  later  the  ovipositor,  are 
thrust,  the  sheath  closing  readily  when  the 
egg  i-  deposited  and  the  ovipositor  with- 
drawn. The  egg-  are  about  3  mm.  long  and 
1  mm.  thick,  creamy  white  in  color,  elongate, 
and  somewhat  kidney-shaped,  with  obtusely 
rounded  ends,  being  slightly  more  rounded  at  one  end  than  at  the 
other:  the  surface  i-  smooth,  without  punctures. 

In  the  latitude  of  southern  Kansas  eggs  were  laid  in  the  corn  plants 
during  the  month  of  June,  where  they  hatched  in  from  7  to  12  day.-, 
the  young,  footle-s  grub  thus  finding  itself  sur- 
rounded with  the  choicest  food. 


Fig.  5. — The  maize  billbug 
6    kenophonu    maidis  i  : 
__~.     Enlarged     three 
times.      'Original.) 


THE    LARVA. 


- 


The  newly  hatched  larvae  are  white,  with  a  light- 
brown  head,  the  head  changing  to  darker  brown 
within  a  few  day-.  The  color  remains  white  in  the 
full-grown  larva?,  with  the  head  chestnut  brown. 
The  length  of  full-grown  living  larvae  range-  from 
15  to  20  mm.  and  the  width  from  4  to  5  mm. 

The  followii  Iption  of  the  full-grown  larva 

was  made  by  Mr.  E.  A.  Schwarz  under  the  name  of 
S.    robnstii8:    from    the    few    alcoholic    specimen-    collected 
Howard  at  Columbia.  S.  C. : a 


bv    Dr 


Length  12  nun. :  color  dingy  white:  head  chestnut  brown,  with  four  vitta?  of 
paler  color,  two  upon  the  occiput,  con veririn z  toward  the  base,  and  one  along 
each  lateral  margin:  tropin  very  dark,  clypeus  paler;  body  fusif"n::.  strongly 

Rei    :■   of  -he  Entomi  logist    Dej    rtment  of  Agriculture,  for  1881  and  188% 

p.  141. 


THE    MAIZE   BILLBUG.  17 

ctirved,  swelling  ventrally  from  the  third  abdominal  joint  posteriorly,  slightly 
recurved  and  rounded  at  anal  extremity.  Head  large,  oblong,  obtusely  angulate 
at  base,  sinuately  narrowed  anteriorly ;  frontal  margin  with  a  shallow  emargina- 
tion  between  the  mandibles ;  upper  surface  with  a  median  channel,  the  occipital 
portion  deeply  incised,  with  raised  edges,  continuing  as  a  shallow  impressed  line 
to  the  middle  of  the  front;  on  either  side  an  engraved  line,  commencing  upon 
the  vertex,  becoming  deeper  after  crossing  the  branches  of  the  Y  suture,  and 
terminating  at  the  frontal  margin  in  a  bristle-bearing  depression ;  sides  and 
vertex  with  several  long  bristles  arising  in  depressions ;  antennae  rudimentary, 
occupying  minute  pits  on  the  frontal  margin  at  the  middle  of  the  base  of  man- 
dibles;  ocelli  a  single  pair,  visible  only  as  translucent  spots  upon  the  anterior 
face  of  the  thickened  frontal  margin,  outside  of  and  closely  contiguous  to  the 
antennae  from  which  they  are  separated  by  the  branches  of  the  Y  suture,  a  few 
pigment  cells  obscurely  visible  beneath  the  surface;  clypeus  free,  transverse, 
trapezoidal,  with  faint  impressions  along  the  base  and  at  the  sides ;  labrum 
small,  elliptical,  bearing  spines  and  bristles,  a  furrow  each  side  of  the  middle, 
forming  three  ridges,  so  that  the  organ,  when  deflected,  appears  three-lobed ; 
mandibles  stout,  triangular,  unarmed,  with  an  obsolete  longitudinal  furrow  on 
the  outer  face;  maxillae  stout,  cardinal  piece  transverse,  basal  piece  elongate, 
bearing  a  palpus  of  two  short  joints,  and  a  small  rounded  lobe,  furnished  at  tip 
with  a  brush  of  spiny  hairs,  the  lobe  concealed  by  the  labium ;  labium  consist- 
ing of  a  large  triangular  mentum,  excavate  beneath,  and  a  hastate  palpiger, 
with  a  deep  median  channel ;  labial  palpi  divergent,  separated  by  the  ligula, 
of  two  joints  subequal  in  length;  ligula  represented  by  a  prominent  rounded 
lobe,  densely  ciliate  on  the  under  surface.  Thoracic  joints  separated  above  by 
transverse  folds ;  the  first  wider,  covered  above  by  a  transverse,  thinly  chitinous 
plate;  the  two  following  similar  to  the  abdominal  joints;  abdominal  joints 
forming  on  the  dorsum  narrow  transverse  folds,  separated  by  two  wider  folds, 
the  anterior  fold  attaining  the  ventral  surface,  the  second  fold  confined  to  the 
dorsum,  eighth  and  ninth  abdominal  joints  longer,  excavate  above,  without 
dorsal  folds;  beneath,  the  first  three  joints  contracted,  the  succeeding  joints 
enlarged,  the  terminal  joint  broadly  rounded,  with  anal  opening  upon  a  fold  at 
its  base ;  sides  of  each  joint  presenting  numerous  longitudinal  folds ;  stigmata 
very  large,  nine  pairs;  the  first  on  the  anterior  margin  of  the  prothorax.  low 
down  upon  the  sides ;  the  remainder  upon  the  sides  of  the  first  eight  abdominal 
joints,  above  the  lateral  prominences,  beginning  upon  the  first  joint  at  the 
middle  of  the  side  and  gradually  rising  to  a  dorsal  position  upon  the  eighth 
joint ;  thoracic  and  last  abdominal  pairs  large,  oval ;  the  intermediate  pairs 
smaller,  elliptical ;  all  with  chitinous  margins  of  dark-brown  color.  The  notice- 
able features  of  this  larva  are  its  cephalic  vittse,  and  conspicuous  spiracles. 

Upon  issuing  from  the  eggshell  the  young  larva?  are  about  5  mm. 
long  and  2  mm.  thick.  They  at  once  begin  feeding  on  the  tissues  of 
the  young  corn  at  the  bottom  of  the  egg  puncture  (fig.  7.  fr),  direct- 
ing  their  burrowing  inward  and  downward  into  the  taproot.  When 
they  finish  eating  the  tender  parts  of  the  taproot  the}7  direct  their 
feeding  upward,  continuing  until  full  grown,  allowing  the  lower 
portion  of  the  burrow  to  catch  the  frass  and  excrement  (fig.  7,  a). 
This  burrowing  of  the  taproot  of  the  young  growing  corn  plant  is 
disastrous  to  the  root  system  (PL  I,  figs.  1,  2)  ;  the  roots,  first  dying 
at  the  tips,  soon  become  of  little  use  to  the  plant,  allowing  it  to  die 
or  to  become  more  or  less  dwarfed  (PL  II).     The  corn  plants  shown 


18 


PAPEIIS    ON    CEREAL   AND    FORACK    INSECTS. 


in  Plate  I  were  collected  in  Kansas  and  forwarded,  in  moist  paper. 
to  Washington,  D.  C..  and  photographed  by  the  official  photographer, 

Mr.  L.  S.  Williams,  and  show  the  injuries  more  clearly,  while  Plate 
II,  photographed  in  the  field,  illustrates  the  effect  on  the  standing 
corn.  Small  plants,  even  those  of  less  than  one-half  inch  in  diameter. 
are  often  recipients  of  eggs  from  which  the  larvae,  on  hatching,  bur- 
row into  the  heart  of  the  plant  and  cut  off  the  growing  bud.  thus 
killing  the  top;  they  then  direct  the  burrowing  downward  only  to 


Fig.  7. — Corn  plant  showing  result  of 
attack  by  the  maize  billhug  :  a.  Larval 
burrow  containing  pupa  in  natural 
position  :  b.  egg  puncture  containing 
ggs.  a,  Reduced  two-thirds;  b.  en- 
larged.     (Original.) 


Fig.  8. — Swamp  grass  (Tripmcum 
dactyloides).  attacked  by  the 
maize  billbug.  Reduced  two- 
thirds.      (Original.) 


devour  the  stub,  leaving  themselves  without  food,  and,  being  footless 
grubs,  they  of  course  perish.  Plants  of  more  than  one-half  inch 
diameter  which  become  infested  with  larvae  make  very  poor  growth. 
being  very  slender,  rarely  reaching  a  height  of  more  than  2  or  3  feet 
before  tasseling  (PI.  II).  and  do  not  produce  shoots  or  ears.  Those 
that  do  not  become  infested  until  they  are  half  grown  may  produce 
small  ears.  Each  larva  inhabits  only  the  one  burrow,  and  if.  owing 
to  any  mishap,  it  becomes  dislodged  from  it.  it  is  powerless  to  rees- 
tablish itself.     The  larva  does  not  become  dislodged  from  the  burrow 


Bui.  95,  Part  II,  Bureau  of  Entomology,  U.  S.  Dept.  of  Agriculture. 


Plate  II. 


Fig.  1.— Corn  Plant  Injured  by  the  Adult  of  the  Maize  Billbuq  (Sphenophorus 
maidiS',  Afterward  Attacked  by  the  Larva.  Fig.  2.— Corn  Plant  Showing  on 
Stalk  the  Effects  of  Feeding  by  Adult  Maize  Billbugs,  and  Effects  on  Roots 
of  Feeding  by  the  Larv/e.  Fig.  3.— Corn  Plant,  much  Distorted,  Showing 
Suckers;  Final  Effects  of  Feeding  of  Adult  Maize  Billbugs. 

All  figures  about  natural  size.     (Original.) 


Bui.  95,  Part  II,  Bureau  of  Entomology,  U.  S.  Dept.  of  Agriculture. 


Plate  III. 


Corn  Plants  Showing  Effects  of  Feeding  of  Maize  Billbuq  in  the  Field. 

Plant  at  left  not  attacked,  the  two  at  right  attacked  by  larva-.     Reduced.     (Original.) 


THE    MAIZE    BILLBUG. 


19 


of  its  own  accord.  Sometimes  there  are  three  or  four  larva?  in  the 
same  plant,  their  burrows  often  running-  into  each  other,  but  this 
does  not  appear  to  discommode  them  in  the  least,  as  they  can,  and 
usually  do.  all  mature.  In  badly  infested  fields  two  larva?  are  quite 
often  in  the  same  plant,  although  one  is  the  usual  number  and  is 
sufficient  to  ruin  the  plant.  The  larva?  are  easily  managed  in  the 
laboratory;  upon  issuing  from  the  eggshell  they  can  be  readily  han- 
dled with  a  soft  camePs-hair  brush  and  placed  inside  a  section  of 
a  cornstalk,  where  they  will  feed  as  readily  as  upon  the  growing 
plant.  As  soon  as  the  section  of  plant  is  fairly  eaten,  and  before, 
decay  sets  in.  the  larva4  must  be  removed 
to  fresh  sections;  keeping  them  thus  sup- 
plied with  fresh  food  they  can  be  reared  to 
maturity. 

The  length  of  the  larval  life  ranges  from 
40  to  50  days,  as  indicated  by  laboratory 
observations  and  checked  by  collections  in 
the  field.  They  begin  maturing  and  pu- 
pating by  the  1st  of  August,  pupation 
reaching  the  maximum  by  the  20th.  and 
with  the  exception  of  a  few  stragglers  all 
are  mature  and  changed  to  pupa?  by  the 
1st  of  September. 

THE    PUPA. 
(Fig.  9.) 

The  larva?,  on  finishing  their  growth, 
descend  to  the  lower  part  of  the  burrow, 
to  the  crown  of  the  taproot,  cutting  the  pith 
of  the  cornstalk  into  fine  shreds  with  which 
they  construct  a  cell  where  the}^  inclose 
themselves  for  pupation. 

The  newly  issued  pupae  are  white,  becom- 
ing darker  after  the  fourth  or  fifth  day.  and 
continue   to   darken  until   just   before  the 
adults  issue.     The  adults  are  reddish  black  in  color 
living  pupa?  ranges  from  16  to  20  mm. 

The  following  description  of  the  pupa  was  made  by  Mr.  E.  A. 
Schwarz,  of  the  Bureau  of  Entomology,  under  the  name  of  S.  ro- 
lustus,  from  the  single  individual  collected  by  Dr.  Howard  at 
Columbia.  S.  C.:G 

Average  length,  IT  millimeters.  Stout,  rostrum  reaching  between  first  pair 
of  tarsi.     Antenna?   but   slightly   elbowed   and   reaching  not   quite  to  beud   of 


Fig.  9 — The  maize  billbug  * 
Pupa  :  a.  ventral  view  :  b, 
dorsal,  view  :  c,  anal  seg- 
ment :  (7.  thoracic  spiracle  ; 
c.  abdominal  spiracle,  a,  b, 
Twice  natural  size  ;  c,  d,  e, 
greatly  enlarged.  (Origi- 
nal.) 


The  length  of 


0  Loc.  cit.,  p.  142. 


20  PAPERS  ON  CEREAL  AND  FORAGE  INSECTS. 

anterior  femora  :md  tibia?.  Eyes  scarcely  discernible.  Face  with  three  pairs 
of  shallow  tubercles,  the  basal  pair  the  largest,  and  each  giving  rise  to  a 
stiff,  brown  hair.  Other  minute  piliferous  tubercles,  especially  near  the  pos- 
terior dorsal  border  of  the  abdominal  joints,  being  very  stout  on  the  preanal 
joint,  or  pygidium,  where  they  form  two  series  of  quadridentate  ridges. 

To  Mr.  Schwarz's  description  the  following  may  be  added: 

Lateral  view:  Body  oblong,  thickest  at  middle;  thorax  depressed  anteriorly; 
abdomen  cylindrical,  tapering  from  seventh  segment;  thoracic  pair  of  spiracles 
very  prominent  (fig.  9,  d),  first  five  pairs  of  abdominal  spiracles  prominent  I  flg. 
0,  (),  the  three  on  the  rear  segments  not  prominent.  Elytra  short,  curving 
ventrally  between  middle  and  hind  legs,  reaching  tarsi  of  hind  leg,  covering 
upper  half  of  femur  of  hind  leg;  middle  leg  resting  on  elytra. 

The  pupae  occur  mostly  during  the  latter  part  of  August  and  first 
part  of  September  and  are  always  to  be  found  in  their  cells  in  the 
larval  burrows  near  the  crown  of  the  taproot  and  nearly  always 
below  the  surface.     The  pupal  period  is  from  10  to  12  days. 

THE    ADULT. 
(Fig.   10.) 

The  adults  are  very  large,  robust,  and  reddish  black  when  newly 
issued,  changing  to  black  wdien  older.  The  original  description  by 
Chittenden0  is  given  here: 

Body  two-fifths  as  wide  as  long,  of  robust  appearance  because  of  the  sub- 
quadrate  thorax,  which  is  nearly  as  wide  as  the  elytra;  general  color  black  or 
piceous,  moderately  shining;  alutaceous  deposit  on  unelevated  surfaces  incon- 
spicuous, appearing  to  be  normally  dark  rufous  or  piceous  velvety  wThen  the 
extraneous  argillaceous  covering  does  not  persist. 

Rostrum  three-fifths  the  length  of  the  thorax,  considerably  arcuate,  strongly 
subequally  compressed,  apex  prolonged  at  the  posterior  angle  with  an  acute 
spine,  producing  the  appearance  of  greater  curvature  of  the  inner  surface,  base 
feebly  protuberant,  moderately  dilated ;  anterior  face  of  apex  broadly  deeply 
concave;  surface  minutely  punctate,  more  distinctly  and  densely  at  base,  base 
moderately  deeply  channeled  with  distinct  deep  interocular  puncture  and  short 
impressed  line. 

Thorax  longer  than  wide,  fully  three-fourths  as  long  as  the  elytra,  sides  usu- 
ally widest  just  in  front  of  middle,  anterior  third  suddenly  and  very  strongly 
arcuate  and  constricted  at  apex,  posterior  two-thirds  or  three-fourths  subparallel, 
or  gradually  narrowing  to  the  base  which  is  feebly  bisinuate.  Vittse  feebly 
elevated,  tending  toward  obsolescence,  moderately  finely  but  distinctly  and 
sparsely  punctate,  more  coarsely  and  densely  at  the  ends;  median  vitta  extend- 
ing from  a  fine  line  and  rapidly  widening  to  a  point  just  in  front  of  the  middle 
where  it  is  broadly  dilated,  then  more  abruptly  narrowed,  extending  in  a  nar- 
rower line  to  near  the  base;  lateral  vittae  sinuous  with  a  tendency  to  become 
confluent  with  the  median  in  the  apical  half,  generally  a  little  wider  in  basal 
half  but  narrower  than  the  median,  branch  wide  but  ill-defined;  interspaces  and 
surface  at  sides  coarsely  foveate-punctate,  punctures  becoming  confluent,  espe- 
cially posteriorly  at  sides.     Scutellum  deeply  broadly  concave. 

°Proc.  Ent.  Soc.  Wash.,  vol.  7,  No.  1,  p.  50,  1905. 


THE   MAIZE   BILLBUG. 


21 


Elytra  little  wider  than  the  thorax ;  striae  usually  deep  and  well  defined, 
distinctly  closely  punctate;  intervals  with  first,  third  and  fifth  elevated,  with 
two  or  more  series  of  rows  of  fine  punctulation ;  first  or  sutural  with  basal 
third  triseriately,  posterior  two-thirds  biseriately  punctulate;  third  widest  and 
most  elevated,  with  four  or  five  rows  of  fine  punctulations ;  fifth  biseriately 
punctulate;  seventh  little  or  not  at  all  more  elevated  than  the  remaining  inter- 
vals; intervals  2,  4,  G,  8,  as  also  7,  more  coarsely  and  closely  uniseriately  punctu- 
late. Pygidium  deeply,  coarsely  and  rather  sparsely  punctate,  with  sparse 
golden  yellow  hairs  proceeding  from  the  punctures  and  forming  a  short  tuft 
each  side,  frequently  abraded. 

Lower  surface  coarsely  and  rather  densely  punctate,  scarcely  less  strongly 
at  the  middle  than  at  the  sides,  punctures  largest  at  the  middle  of  the  meta- 
thorax.     Punctures  of  the  metepisterna    (side  pieces)    more  or  less  confluent. 
Second,  third  and  fourth  abdominal  segments 
nearly  uniformly  punctured  throughout,  like 
the  legs. 

$ . — First  abdominal  segment  very  con- 
cave; pygidium  truncate  at  apex. 

$  . — First  ventral  scarcely  different ;  pygid- 
ium narrowed  and  rounded  at  apex. 

Aside  from  the  differently  shaped  pygidium 
and  the  slightly  shorter  and  less  compressed 
rostrum  there  is  little  difference  between  the 
sexes. 

Length.  10-15  mm.,  width,  4.5-6.0  mm. 

The  adults  begin  to  issue  about  the 
middle  of  August  and  continue  to  do  so 
until  the  middle  of  September.  Some 
of  them  leave  the  pupal  cell,  but  most 
of  them  remain  there  for  hibernation. 
The  adults  that  leave  the  pupal  cell  in 
the  late  summer  disappear;  continued 
search  in  every  situation  until  Decem- 
ber failed  to  reveal  a  single  individual. 
It  is  evident  that  they  left  the  cornfield  in  which  they  developed, 
and  it  is  very  probable  that  they  found  their  way  to  some  dense, 
coarse  grass  (T.  dactyl 'oid 'es) ,  which  is  abundant  in  the  locality, 
The  adults  hibernating  in  the  pupal  cells  issue  from  them  in  late 
spring,  about  the  time  young  corn  is  sprouting.  The  beetles  are 
rarely  observed  on  account  of  their  quiet  habits  and  because  they 
are  covered  with  mud — a  condition  which  is  more  or  less  common 
among  several  species  of  this  genus  and  is  caused  by  a  waxy  exuda- 
tion of  the  elytra,  to  which  the  soil  adheres.  The  presence  of  the 
adults  of  this  species  in  a  cornfield  is  made  evident  by  the  withering 
of  the  top  leaves  of  very  young  corn  plants,  the  plants  having  been 
severely  gouged.  The  adults  kill  the  small  plants  outright  and  in- 
jure the  larger  ones  beyond  repair.  After  the  plants  grow  10  to  15 
inches  tall  they  do  not  kill  them,  but  gouge  out  such  large  cavities 
in  the  stalks  that  they  become  twisted  into  all  sorts  of  shapes  (PI.  I, 


Fig.  10.— The  maize  billbug  :  Adult. 
Four  times  natural  size.  (Origi- 
nal.) 


22  PAPERS  ON  CEREAL  AND  FORAGE  INSECTS. 

fig.  3).  The  attacked  plants  sucker  profusely,  affording  young, 
tender  growth  for  the  beetles  to  feed  upon,  even  for  many  days  after 
the  noninfested  plants  have  become  hard.  The  corn  plants  injured 
by  S.  maidis  resemble  somewhat  corn  plants  injured  by  the  lesser 
corn  stalk-borer  (Diatrcea  saccharalis) ,  and  are  easily  distinguished 
from  plants  injured  by  the  smaller  species  of  Sphenophorus  owing 
to  the  fact  that  the  punctures  of  the  smaller  species  are  not  always 
fatal  to  the  plants,  which,  however,  in  unfolding  their  leaves,  show  a 
row  or  series  of  rows  of  round  or  oblong  holes  in  them. 

The  females  issuing  from  hibernation  feed  on  j'oung  corn  for  a 
few  days  before  beginning  to  deposit  their  eggs.  The  egg  punctures 
are  made  by  the  female  in  the  side  of  the  cornstalk  (fig.  7,  h)  be- 
neath the  outer  sheath.  These  egg  punctures  are  not  injurious  to 
the  plants,  being  only  small  grooves,  about  5  mm.  long  and  3  mm. 
deep,  in  which  the  eggs  snugly  fit. 

NUMBER   OF   GENERATIONS. 

There  is  only  one  generation  a  year.  The  eggs  occur  throughout 
June,  larvae  from  early  June  until  September,  pupae  from  the  first 
part  of  August  until  the  last  part  of  September,  and  adults  from 
the  middle  of  August  until  the  first  part  of  August  of  the  following 
year. 

RECORDS    OF    DEPREDATIONS. 

The  depredations  of  this  species  have  probably  been  confused  with 
that  of  other  species,  the  first  and  only  known  record  of  its  attack 
on  young  corn  being  that  made  by  Dr.  Howard,  at  Columbia,  S.  C. 
During  the  season  of  1910  both  adults  and  larvae  were  numerous  in 
cornfields  in  lowlands  in  southern  Kansas  and  northern  Oklahoma, 
doing  serious  damage  in  some  instances.  They  were  frequently 
found  in  uplands,  but  not  in  injurious  numbers. 

REMEDIAL   MEASURES. 

The  knowledge  of  the  hibernating  habits  of  the  insect  suggests  an 
effective  remedy  in  the  pulling  up  and  burning  of  the  stubble,  which 
is  also  the  most  practical  means  of  destroying  the  lesser  coin  stalk- 
borer  (Diatrcea  saccharalis).  The  beetles  remain  in  the  taproot  of 
the  corn  plants  until  spring,  allowing  the  fanner  abundant  time  to 
destroy  them.  Care  must  be  taken,  however,  in  pulling  up  the 
infested  stalks  or  else  they  will  break  off  above  the  beetle,  leaving 
the  pest  in  the  ground.  The  infested  stalks,  having  a  very  poor 
root  system,  are  easily  pulled.  Spraying  the  young  corn  plants  with 
arsenical  fluids  at  the  time  the  beetles  are  making  their  attack  is  a 
very  laborious  procedure  and  not  very  effective. 

o 

UNIVERSITY  OF  FLORIDA  I  \  J  1 4    »  I    ]  ^/I  ii»  Ml 


